Viscoelasticity of articular cartilage: Analysing the effect of induced stress and the restraint of bone in a dynamic environment

Abstract

The aim of this study was to determine the effect of the induced stress and restraint provided by the underlying bone on the frequency-dependent storage and loss stiffness (for bone restraint) or modulus (for induced stress) of articular cartilage, which characterise its viscoelasticity. Dynamic mechanical analysis has been used to determine the frequency-dependent viscoelastic properties of bovine femoral and humeral head articular cartilage. A sinusoidal load was applied to the specimens and out-of-phase displacement response was measured to determine the phase angle, the storage and loss stiffness or modulus. As induced stress increased, the storage modulus significantly increased (p < 0.05). The phase angle decreased significantly (p < 0.05) as the induced stress increased; reducing from 13.1° to 3.5°. The median storage stiffness ranged from 548 N/mm to 707 N/mm for cartilage tested on-bone and 544 N/mm to 732 N/mm for cartilage tested off-bone. On-bone articular cartilage loss stiffness was frequency independent (p > 0.05); however, off-bone, articular cartilage loss stiffness demonstrated a logarithmic frequency-dependency (p < 0.05). In conclusion, the frequency-dependent trends of storage and loss moduli of articular cartilage are dependent on the induced stress, while the restraint provided by the underlying bone removes the frequency-dependency of the loss stiffness.

Viscoelastic properties of human periodontal ligament: Effects of the loading frequency and location

“…Since the 1990s, dynamic mechanical analysis (DMA) has been used to investigate the viscoelastic properties of biological tissue, such as lens, 8 articular cartilage, 9 cardiovascular tissue, 10 bladder tissue, 11 and so on. The frequency dependency of the storage (E 0 ) and loss (E 00 ) moduli of various biomaterials was obtained from DMA testing.…”

Towards viscoelastic characterisation of the human ulnar nerve: An early assessment using embalmed cadavers

“…ElectroForce 3200 testing machine running Bose WinTest 4.1 DMA software (Bose Corporation, ElectroForce Systems Group, Minnesota, USA). DMA has previously been used to quantify the storage and loss properties of a variety of biological tissues[22,[25][26][27][28] and orthopaedic implants…”

Development of a Three-Dimensional Bioengineered Platform for Articular Cartilage Regeneration

“…However, other mechanical properties, including storage and loss modulus, showed significant differences with native cartilage and even higher differences compared to PCL and PCL/RAD scaffolds. This means that the peptide constructs are more elastic and viscous than native cartilage, explained by their soft and highly elastic fibers in wet conditions, which could entail non-desired mechanical responses as joint replacements [59]. Moreover, after mechanical testing, RAD composites were unable to recover the initial shape, excluding the possibility to repeat measurements with the same sample and therefore, impeding the enforcement of constant and repeated stresses, leading to low durability and less resistance to repetition of compressive loads and deformations when placed in patients' joints, whereas 3D printed scaffolds were able to return to their initial shape to reload the stress.…”